Consolidated Statement of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in-Capital	Retained Earnings (Deficit)
Balance at Dec. 31, 2013	$ 1,348,549	$ 996	$ (5,362)	$ 985,023	$ 367,892
Balance, shares at Dec. 31, 2013		100,699	167
Issuance of common stock	(176)	$ 0		(176)
Issuance of common stock, shares		0
Stock-based compensation	22,360	$ 5		22,355
Stock-based compensation, shares		762
Treasury stock - tax withholdings	(5,309)		$ (5,309)
Treasury stock - tax withholdings, shares		(119)	119
Net income (loss)	506,877				506,877
Balance at Dec. 31, 2014	1,872,301	$ 1,001	$ (10,671)	1,007,202	874,769
Balance, shares at Dec. 31, 2014		101,342	286
Issuance of common stock	462,833	$ 368		462,465
Issuance of common stock, shares		36,800
Stock-based compensation	27,405	$ 7		27,398
Stock-based compensation, shares		1,156
Treasury stock - tax withholdings	(2,949)		$ (2,949)
Treasury stock - tax withholdings, shares		(222)	222
Net income (loss)	(40,248)				(40,248)
Balance at Dec. 31, 2015	2,319,342	$ 1,376	$ (13,620)	1,497,065	834,521
Balance, shares at Dec. 31, 2015		139,076	508
Issuance of common stock	766,670	$ 943		765,727
Issuance of common stock, shares		94,300
Stock-based compensation	25,771	$ 12		25,759
Stock-based compensation, shares		3,317
Equity component of senior unsecured convertible notes, net	56,720			56,720
Treasury stock - tax withholdings	(2,330)		$ (2,330)
Treasury stock - tax withholdings, shares		(349)	349
Net income (loss)	(243,016)				(243,016)
Balance at Dec. 31, 2016	$ 2,923,157	$ 2,331	$ (15,950)	$ 2,345,271	$ 591,505
Balance, shares at Dec. 31, 2016		236,344	857